I haven't found a pattern yet, but I'm not the type to analyze the game, more the roleplayer.
What helps my sims getting their awards is spamming the accolades event. Every sunday I will switch to a household with a famous sim, have them invite a handfull of also famous friends and go to the accolade event as a group. The moment I see an unfamilar sim spawn at the elevator during the event, I shift-click delete it.
Sure enough, one or more of my sims will get called up to receive a prize, either my active household or my other played sims. No prior nomination required.
